WASHINGTON (CNN) - Members of Congress may have been grateful to leave the raucous town halls of August behind last week, when their summer recess ended. The break was a short one.

Busloads of those town hall critics have been heading for the Hill all week ahead of a major Saturday showdown.

Starting Thursday, the day after President Obama delivered his address on health care reform to a joint session of Congress, opponents of his proposal made a major lobbying push, the kickoff of the annual three-day March on Washington organized by FreedomWorks.

Hundreds of them gathered Thursday at the D.C. Armory to officially prepare for face-to-face meetings with members of Congress.

Some sported tea bags, the symbol of the Tea Party movement, pinned to their hats. Others wore T-shirts advertising FreedomWorks, the controversial conservative group that has found itself at the center of some of the summer's fiercest town hall battles.

Many expressed delight at South Carolina Republican Rep. Joe Wilson's outburst during the president's Wednesday address.

WASHINGTON (CNNMoney.com) - In an effort to cast health care reform as helpful to more Americans, President Obama on Saturday pounded home a new statistic: Nearly 50% of people under 65 have gone without coverage for at least one month over a decade.

"It can happen to anyone," Obama said in his weekly address. "In the United States of America, no one should have to worry that they'll go without health insurance - not for one year, not for one month, not for one day. And once I sign my health reform plan into law - they won't."

The new figure comes from a Treasury Department analysis of survey data collected by the University of Michigan. The data tracked health insurance coverage through phone interviews with some 17,000 individuals from 1997 to 2006.

It appears to be the first such analysis of its kind to look at the population of uninsured Americans over a lengthy period of time.